IKEv2 Denial of Service via malformed fragmentation
Priority MEDIUM 40CWE-193Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- Denial of service
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 13 fixed, 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat. Impact type from CWE-193 and the CVSS impact.
Summary
An invalidly formatted IKEv2 fragment causes the Libreswan pluto daemon to crash and restart. Continued exploitation would cause a denial of service. The function reassemble_v2_incoming_fragments() would ignore unknown outer payloads but still store these in a fixed size array msg_digest.digest[PAYLIMIT]. An off-by-one error in the assertion PASSERT(logger, md->digest_roof < elemsof(md->digest)) causes the daemon to abort. No remote code execution is possible. Any configuration that allows IKEv2 connections that do not set fragmentation=no are vulnerable. IKEv1 is not affected.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00598 48th percentileScored 2026-11-07
Fix Partial libreswan (The Libreswan Project): 5.3.1Red Hat: 12 advisoriesRed Hat: 13 fixed, 2 without a fix
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- Yes
- Technical impact
- Partial
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| The Libreswan Project | libreswan | 4.6 – 5.3 | 5.3.1 | Patch available | CNA |
- libreswan VendorThe Libreswan Project Affected 4.6 – 5.3 Fixed in 5.3.1 Patch available CNA
CPE configurations NVD · 1
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:libreswan:libreswan:*:*:*:*:*:*:*:* | 4.6 to before 5.3.1 | Vulnerable | The Libreswan Project |
- cpe:2.3:a:libreswan:libreswan:*:*:*:*:*:*:*:* Versions 4.6 to before 5.3.1 Vulnerable ·The Libreswan Project
Remediation
- Fix · CNA libreswan (The Libreswan Project) Fixed in 5.3.1
Red Hat 12 advisories
- RHSA-2026:72287 Released 2026-09-28 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream E4S (v.8.8) libreswan-4.9-3.el8_8.3
- Red Hat Enterprise Linux AppStream TUS (v.8.8) libreswan-4.9-3.el8_8.3
- RHSA-2026:63044 Released 2026-09-09 · Red Hat rating ImportantOpenShift Container Platform 4.19.46 bug fix and security update
- Red Hat OpenShift Container Platform 4.19 rhcos-aarch64-4.19.9.6.202609021231-0, rhcos-ppc64le-4.19.9.6.202609021231-0, rhcos-s390x-4.19.9.6.202609021231-0 +1
- RHSA-2026:63041 Released 2026-09-08 · Red Hat rating ImportantOpenShift Container Platform 4.21.32 bug fix and security update
- Red Hat OpenShift Container Platform 4.21 rhcos-aarch64-4.21.9.6.202609021100-0, rhcos-ppc64le-4.21.9.6.202609021100-0, rhcos-s390x-4.21.9.6.202609021100-0 +1
Show 9 more Red Hat advisories
- RHSA-2026:63100 Released 2026-09-08 · Red Hat rating ImportantOpenShift Container Platform 4.20.37 bug fix and security update
- Red Hat OpenShift Container Platform 4.20 rhcos-aarch64-4.20.9.6.202609021029-0, rhcos-ppc64le-4.20.9.6.202609021029-0, rhcos-s390x-4.20.9.6.202609021029-0 +1
- RHSA-2026:61779 Released 2026-08-31 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream E4S (v.9.2) libreswan-4.9-5.el9_2.5
- RHSA-2026:61258 Released 2026-08-31 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream E4S (v.9.4) libreswan-4.12-3.el9_4.2
- RHSA-2026:57741 Released 2026-08-20 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream EUS (v.9.6) libreswan-4.15-8.el9_6.1
- RHSA-2026:55449 Released 2026-08-17 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream EUS (v. 10.0) libreswan-5.2-1.el10_0.5
- RHSA-2026:46986 Released 2026-07-27 · Red Hat rating Importantlibreswan security update
- Fast Datapath for Red Hat Enterprise Linux 9 libreswan-5.3.2-1.el9fdp
- RHSA-2026:46398 Released 2026-07-27 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream (v. 10) libreswan-5.3.2-1.el10_2, libreswan-minimal-5.3.2-1.el10_2
- RHSA-2026:46397 Released 2026-07-27 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream (v. 9) libreswan-4.15-10.el9_8
- RHSA-2026:46396 Released 2026-07-27 · Red Hat rating Importantlibreswan security update
- Red Hat Enterprise Linux AppStream (v. 8) libreswan-4.12-2.el8_10.6
Vendor assessments
Red Hat
Red Hat rating: Important. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet |
| Fast Datapath for Red Hat Enterprise Linux 9 | Fixed | RHSA-2026:46986 |
| Red Hat Enterprise Linux AppStream (v. 10) | Fixed | RHSA-2026:46398 |
| Red Hat Enterprise Linux AppStream (v. 8) | Fixed | RHSA-2026:46396 |
| Red Hat Enterprise Linux AppStream (v. 9) | Fixed | RHSA-2026:46397 |
| Red Hat Enterprise Linux AppStream E4S (v.8.8) | Fixed | RHSA-2026:72287 |
| Red Hat Enterprise Linux AppStream E4S (v.9.2) | Fixed | RHSA-2026:61779 |
| Red Hat Enterprise Linux AppStream E4S (v.9.4) | Fixed | RHSA-2026:61258 |
| Red Hat Enterprise Linux AppStream EUS (v. 10.0) | Fixed | RHSA-2026:55449 |
| Red Hat Enterprise Linux AppStream EUS (v.9.6) | Fixed | RHSA-2026:57741 |
| Red Hat Enterprise Linux AppStream TUS (v.8.8) | Fixed | RHSA-2026:72287 |
| Red Hat OpenShift Container Platform 4.19 | Fixed | RHSA-2026:63044 |
| Red Hat OpenShift Container Platform 4.20 | Fixed | RHSA-2026:63100 |
| Red Hat OpenShift Container Platform 4.21 | Fixed | RHSA-2026:63041 |
Not affected: 8 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux AppStream E4S (v.8.8)
- Red Hat Enterprise Linux AppStream E4S (v.9.2)
- Red Hat Enterprise Linux AppStream E4S (v.9.4)
- Red Hat Enterprise Linux AppStream EUS (v. 10.0)
- Red Hat Enterprise Linux AppStream EUS (v.9.6)
- Red Hat Enterprise Linux AppStream TUS (v.8.8)
Timeline
- 2026-10-02 Threatist record created from CVE-2026-12413
- 2026-10-03 Alias added: GHSA-vj68-68x2-jwjq
- 2026-11-05 Affected versions changed · Red Hat
References
More The Libreswan Project Libreswan vulnerabilities
- TI-2023-09114 Libreswan 4.9 allows remote attackers to cause a denial of service (assert failure and… CVSS 3.1MEDIUM 6.5
- TI-2013-05949 Race condition in the libreswan.spec files for Red Hat Enterprise Linux (RHEL) and Fedora… CVSS 2.0HIGH 9.3
- TI-2023-02152 Uncontrolled resource consumption in libreswan CVSS 3.1HIGH 7.5
- TI-2026-37395 IKEv2 Denial of Service via RSA-SHA1 (PKCS#1 RSASSA-PKCS1-v1_5) authentication payload CVSS 3.1HIGH 8.1
- TI-2026-37394 IKEv1 Denial of Service via RSA-SHA1 (PKCS#1 Version 1.5 Encrypted) authentication payload CVSS 3.1HIGH 8.1
- TI-2023-14401 pluto in Libreswan before 4.11 allows a denial of service (responder SPI mishandling and… CVSS 3.1HIGH 7.5
Sources
- CVE-2026-12413 · CVE Program
- CVE-2026-12413 · NVD
- FIRST EPSS
- GHSA-vj68-68x2-jwjq · GitHub Advisory Database · CC BY 4.0
- CVE-2026-12413 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences